
Heltec Wireless Stick is a development board based on the ESP32 microcontroller using XTENSA architecture.
This board features a maximum CPU frequency of 240 MHz and 8MB flash memory.
About Heltec Wireless Stick
Slim ESP32 board with LoRa support and USB-C - great for wearable or compact LoRa-based IoT builds.
Heltec Wireless Stick Technical Specifications
🛰️ Connectivity
🧠 Microcontroller
✨ Features
- 40 digital IO pins
- 16 external interrupt pins
- 16 analog input pins
- 19 PWM pins
Heltec Wireless Stick Pinout

Heltec Wireless Stick Pin Mappings
Below you can find the Heltec Wireless Stick pinout. This development board provides 40 digital IO pins, out of which 16 can be used as external interrupt pins, 16 as analog input pins and 19 pins have Pulse-Width Modulation (PWM).
| Pin | Analog | Touch | PWM | Other |
|---|---|---|---|---|
| 0 | A11 | T1 | KEY_BUILTIN | |
| 1 | PWM | TX | ||
| 2 | A12 | T2 | PWM | |
| 3 | PWM | RX | ||
| 4 | A10 | T0 | PWM | SDA_OLED |
| 5 | PWM | SCK | ||
| 12 | A15 | T5 | PWM | |
| 13 | A14 | T4 | PWM | |
| 14 | A16 | T6 | PWM | RST_LoRa |
| 15 | A13 | T3 | PWM | SCL_OLED |
| 16 | PWM | RST_OLED | ||
| 18 | PWM | SS | ||
| 19 | PWM | MISO | ||
| 21 | PWM | SDA Vext | ||
| 22 | PWM | SCL | ||
| 25 | A18 | PWM | LED_BUILTIN DAC1 LED | |
| 26 | A19 | PWM | DAC2 DIO0 | |
| 27 | A17 | T7 | PWM | MOSI |
| 32 | A4 | T9 | PWM | |
| 33 | A5 | T8 | PWM | |
| 34 | A6 | DIO2 | ||
| 35 | A7 | DIO1 | ||
| 36 | A0 | |||
| 39 | A3 |
Default Tools for Heltec Wireless Stick
| Bootloader tool | esptool_py |
| Uploader tool | esptool_py |
| Network uploader tool | esp_ota |
| Bootloader address | 0x1000 |
| Flash mode | dio |
| Boot mode | dio |
| Maximum upload size | 3264 Kb (3342336 B) |
| Maximum data size | 320 Kb (327680 B) |
The Heltec Wireless Stick development board by default uses esptool_py uploader tool, network uploader tool for Over-the-air (OTA) uploads and esptool_py bootloader tool. The bootloader starts at address "0x1000". Flash mode and boot mode for Heltec Wireless Stick development board by default is dio and dio respectively.


